I ordered a replacement canvas for my previous camper (97 Jayco 21 SLD) and it took a day for four of us who didn't have a clue about what we were doing to remove the old canvas and install the new one...this was a few years ago, but this website looks familiar! We were motivated by the fact that we did this in a campground and not our back yard and needed to sleep in it the same night!
If you go this route, make sure you figure out a strategy for connecting the canvas to the bottom of the beds - the replacement canvas came with velcro - so, I had to make a trip to a hardware store to buy a heavy duty staple gun. Have plenty of canvas screws with plastic washers on hand and a variety of putty knives, pocket knives, flathead screw drivers, and whatever other do-hickies you have to help slide the canvas in to the little groove. Gloves came in handy in protecting fingers from some of the tight pulling you have to do.
We had fun and I would not hesitate to do it again!